Normal Levels of Plasma Free Carnitine and Acylcarnitines in Follow-Up Samples From a Presymptomatic Case of Carnitine Palmitoyl Transferase 1 (CPT1) Deficiency Detected Through Newborn Screening in Denmark
1 Graduate School of Health and Medical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet2 Section of Gynaecology, Obstetrics and Paediatrics, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet3 Studienævnet for Medicin, BSc + MSc programme, Faculty of Health and Medical Sciences, Københavns Universitet4 unknown5 Institut for Klinisk Medicin - Børneafd., Herning6 Institut for Human Genetik7 Institut for Klinisk Medicin - Molekylær Medicinsk Forsk.enhed8 Graduate School of Health and Medical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet
Carnitine palmitoyl transferase (CPT) 1 A deficiency is a rare disorder of hepatic long-chain fatty acid oxidation. CPT1 deficiency is included in newborn screening programs in a number of countries to allow presymptomatic detection and early treatment of affected patients. We present a case of presymptomatic CPT1A deficiency detected through newborn screening in Denmark with diagnostic levels of carnitine and acylcarnitines in the initial dried blood spot. Levels of plasma-free carnitine and acylcarnitines in follow-up samples were normal, but reverted to diagnostic levels when the patient developed clinical symptoms at the age of 8 months. At that time, a diagnosis of CPT1A deficiency was confirmed by sequence analysis of the CPT1A gene revealing homozygosity for a novel c.167C>T variation in exon 3. Enzyme activity measurements showed a relatively mild enzyme defect with a decreased residual enzyme activity of 17–25%. We conclude that CPT1A gene testing and/or enzyme assay is mandatory to confirm an abnormal newborn screen suggesting CPT1A deficiency to avoid delayed diagnoses.